Ability to filter-out driver-specific "success" shader compilation logs.

Intel drivers on Windows print out "No errors." when the shader is
compiled/linked successfully. I consider that as unnecessary spam and
filter it out.

src/Magnum/AbstractShaderProgram.cpp

@@ -44,6 +44,11 @@
 
 namespace Magnum {
 
+namespace Implementation {
+    /* Defined in Implementation/driverSpecific.cpp */
+    bool isProgramLinkLogEmpty(const std::string& result);
+}
+
 Int AbstractShaderProgram::maxVertexAttributes() {
     GLint& value = Context::current()->state().shaderProgram->maxVertexAttributes;
 
@@ -371,7 +376,7 @@ bool AbstractShaderProgram::link(std::initializer_list<std::reference_wrapper<Ab
                 << message;
 
         /* Or just warnings, if any */
-        } else if(!message.empty()) {
+        } else if(!message.empty() && !Implementation::isProgramLinkLogEmpty(message)) {
             Warning out;
             out.setFlag(Debug::NewLineAtTheEnd, false);
             out.setFlag(Debug::SpaceAfterEachValue, false);

src/Magnum/Implementation/driverSpecific.cpp

@@ -29,6 +29,38 @@
 
 namespace Magnum {
 
+namespace Implementation {
+
+/* Used in Shader.cpp (duh) */
+bool isShaderCompilationLogEmpty(const std::string&);
+bool isShaderCompilationLogEmpty(const std::string& result) {
+    #ifdef CORRADE_TARGET_WINDOWS
+    /* Intel Windows drivers are too chatty */
+    if((Context::current()->detectedDriver() & Context::DetectedDriver::IntelWindows) && result == "No errors.\n")
+        return true;
+    #else
+    static_cast<void>(result);
+    #endif
+
+    return false;
+}
+
+/* Used in AbstractShaderProgram.cpp (duh) */
+bool isProgramLinkLogEmpty(const std::string&);
+bool isProgramLinkLogEmpty(const std::string& result) {
+    #ifdef CORRADE_TARGET_WINDOWS
+    /* Intel Windows drivers are too chatty */
+    if((Context::current()->detectedDriver() & Context::DetectedDriver::IntelWindows) && result == "No errors.\n")
+        return true;
+    #else
+    static_cast<void>(result);
+    #endif
+
+    return false;
+}
+
+}
+
 auto Context::detectedDriver() -> DetectedDrivers {
     if(_detectedDrivers) return *_detectedDrivers;
 

src/Magnum/Shader.cpp

@@ -50,6 +50,11 @@ typedef char GLchar;
 
 namespace Magnum {
 
+namespace Implementation {
+    /* defined in Implementation/driverSpecific.cpp */
+    bool isShaderCompilationLogEmpty(const std::string& result);
+}
+
 namespace {
 
 std::string shaderName(const Shader::Type type) {
@@ -770,7 +775,7 @@ bool Shader::compile(std::initializer_list<std::reference_wrapper<Shader>> shade
                 << message;
 
         /* Or just warnings, if any */
-        } else if(!message.empty()) {
+        } else if(!message.empty() && !Implementation::isShaderCompilationLogEmpty(message)) {
             Warning out;
             out.setFlag(Debug::NewLineAtTheEnd, false);
             out.setFlag(Debug::SpaceAfterEachValue, false);